Problem: The sum of $5$ consecutive odd numbers is $75$. What is the first number in this sequence?
Call the first number in the sequence $x$ The next odd number in the sequence is $x + 2$ The sum of the $5$ consecutive odd numbers is: $x+ (x + 2)+ (x + 4)+ (x + 6)+ (x + 8) = 75$ $5x + 20= 75$ $5x = 55$ $x = 11$ Thus, the first number is $11$.